Passively aligned integrated optical head including light source, detector, and optical element and methods of forming same

ABSTRACT

An integrated optical head, such as, for a disk drive, preferably includes an optically transparent substrate. The substrate has a diffractive optical element formed on one face and a plurality of electrical contact pads exposed on the other face. A light source is positioned to emit light through the substrate, through the diffractive optical element, and toward data storage media. The light source includes a plurality of electrical contact pads corresponding to the plurality of electrical contact pads exposed on the face of the substrate. An optical detector is positioned to detect light reflected from the data storage media, through the diffractive optical element, and through the substrate. The optical detector includes a plurality of exposed electrical contact pads corresponding to the plurality of electrical contact pads exposed on the face of the substrate. The substrate and the light source and optical detector are passively aligned using solder bumps between pairs of contact pads. A mechanical passive alignment arrangement is also disclosed.

FIELD OF THE INVENTION

The present invention relates to the field of optics and, moreparticularly, to an integrated optical head, such as for use in a diskdrive.

BACKGROUND OF THE INVENTION

Many typical computer systems include a disk drive cooperating withstorage media to permit storage and retrieval of data. A typical opticaldisk drive includes an optical head that conventionally uses a laser totransmit light to the optical disk. Light reflected from the surface ofthe disk is detected by an optical detector and processed to read datafrom the disk. An example of such an optical head is disclosed, forexample, in U.S. Pat. No. 5,204,516 titled "Planar Optical Scanning HeadHaving Deficiency-Correcting Grating" by Opheij. The size of the variousoptical head components, however, are often too large for many desiredapplications and many market demands. Also, as densities of integratedcircuits and system boards increase, the demand for smaller componentsincreases. Additionally, the production process for a conventionaloptical head requires that the laser be excited or turned-on (i.e.,"active alignment") for alignment of the laser, the detector, and theoptical elements. An example of active alignment processes isillustrated and described in an article published in Optical Engineering(June 1989) titled "Holographic Optical Head For Compact DiskApplications" by Lee.

Unfortunately, these active alignment requirements are complex, timeconsuming, and relatively expensive. Further, the level of sizereduction in the vertical direction of an optical head is limited. Inaddition, the relatively large size of the elements of an optical headwhich can be manipulated is determined by the need for active alignment.

SUMMARY OF THE INVENTION

With the foregoing background in mind, it is therefore an object of thepresent invention to provide an optical head, such as for a disk drive,and related methods which is more compact and less expensive tomanufacture.

This and other objects, advantages, and features of the presentinvention are provided by an integrated optical head that relies onpassive alignment of the various components. The integrated optical headpreferably includes an optically transparent substrate having first andsecond faces.

The substrate may include a diffractive optical element formed on thesecond face of the substrate. An optical light source, such as a laser,is positioned adjacent the first face of the substrate to transmit lightthrough the substrate, through the diffractive optical element, andtoward a target, such as optical storage media. An optical detector ispositioned adjacent the first surface of the substrate to detect lightreflected from the storage media, through the diffractive opticalelement, and through the substrate. Passive alignment means ispositioned between the first surface of the substrate and at least oneof the laser and the optical detector for passively aligning the laseror the optical detector with respect to the substrate. Accordingly, thelaser and detector may also be aligned with the optical elements on thesecond surface of the substrate.

An optical head according to the present invention may provide a sizereduction of more than three times compared to the prior art, in part,based upon photolithographically shaped and placed refractive opticalelements, as well as diffractive optical elements. Further, the laserand detector are preferably also accurately and passively aligned bymeans of photolithography. More particularly, in one embodiment, passivealignment is achieved by the wetted area and volume of solder inopposing alignment areas provided by contact pads.

In another embodiment, a second transparent substrate is aligned andjoined to the first substrate.

The second substrate may carry one or more optical elements. Accordingto this aspect of the invention, alignment areas in the form of benchesor other mechanical features may be formed in one surface and matingrecesses, for example, may be formed in the other surface. Adhesiveattachment areas, which may overlap the alignment areas, hold thesubstrates together. Alignment may also be accomplished at the waferlevel by having the elements of each die accurately placed usingphotolithography to accurately align the two wafers. The assembled diescan then be diced without the individual alignment means or steps beingrequired for connecting the first and second substrates.

Methods of forming an optical head are also provided according to thepresent invention. A method of forming an optical head preferablyincludes forming at least one optical element on a first face of atransparent substrate and positioning a laser adjacent the first face ofthe substrate so as to emit light through the substrate, through the atleast one optical element, and toward the data storage media. An opticaldetector preferably is positioned adjacent the first face of thetransparent substrate adjacent the laser to detect light reflected fromthe data storage media, through the substrate, and to the opticaldetector.

The laser, the optical detector, and/or the at least one optical elementon the substrate may passively aligned using either the contact pads andsolder bumps, or the mechanical alignment as discussed above.

An integrated optical head and the related methods according to thepresent invention advantageously provide a significantly smaller opticalhead for fabrication without the need for exciting or turning on thelaser light source to actively align the components. The integratedoptical head according to the present invention overcomes thedisadvantages of the prior art so that the wavelength of the laser isleft as the predominant limiting factor in size reduction instead ofother considerations.

BRIEF DESCRIPTION OF THE DRAWINGS

Some of the objects and advantages of the present invention having beenstated, others will become apparent as the description proceeds whentaken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic view of an integrated optical head according tothe present invention;

FIG. 2 is a fragmentary side perspective view of an integrated opticalhead according to the present invention;

FIG. 3 is a side elevational view of an integrated optical headaccording to the present invention;

FIG. 4 is side elevational view of the integrated optical head as shownin FIG. 3 rotated ninety degrees.

FIG. 5 is a plan view of the component side of a first transparentsubstrate of an integrated optical head according to the presentinvention;

FIG. 6 is a plan view of a holographic optical element of a firsttransparent substrate of an integrated optical head according to thepresent invention;

FIG. 7 is a plan view of a refractive lens surface of a secondtransparent substrate of an integrated optical head according to thepresent invention;

FIG. 8 is a plan view of diffractive optical elements of an integratedoptical head according to the present invention;

FIG. 9 is an enlarged view of mask portions of FIG. 4 according to thepresent invention;

FIG. 10 is a perspective view showing an article including two wafersaccording to the present invention;

FIGS. 11A-11D are vertical fragmentary sectional views of examplealignment features according to the present invention; and

FIG. 12 is a vertical sectional view of a substrate showing a method ofcreating a hybrid microlens for an integrated optical head according tothe invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theillustrated embodiments set forth herein. Rather, these illustratedembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the invention to thoseskilled in the art. Like numbers refer to like elements throughout, andprime and double prime notation are used to indicate similar elements inalternative embodiments.

FIG. 1 is an optical design schematic of an assembly according to theinvention for use in detecting an optical track on a storage media. Alight source 10 directs coherent light, with a dispersion angle offifteen degrees, upward through an object distance d1 through adiffractive element (DOE) not shown and to a refractive lens 12. The DOEdivides the light into a number of beams, only three of which are shownas a plurality of rays in FIG. 1. The beams are focused on surface 14located at image distance d2 from the lens 12. The spot size and spacingof the light on the image surface 14 determines the tracking accuracyand therefore the amount of information that can be stored on the media.The size to which the spot can be reduced is in the instant design,approximately 0.020 mm. In the design of FIG. 1, the refractive lens 12must have a significant curvature in order to focus the light to 0.020mm spots on the media. The spots of light are spaced approximately 0.100mm from each other on the media to limit crosstalk noise. As would bereadily understood by those skilled in the art the optical head can bepositioned by the illustrated positioning means 29.

If a design were attempted using a single lens as taught in the priorart, the lens curvature required to focus the laser light to 0.020 mmspots in this compact architecture would control the dimensions of thesingle lens. Thus the use of a single lens as taught in the prior artfor reducing the size of optical heads, is a limiting factor in sizereduction of the entire optical head assembly. This factor is one of thereasons that multiple lenses are employed in the instant inventioninstead of a single lens.

The distance d1 is used to advantage to provide an adequately wide beamat the DOE as shown later with respect to FIG. 7. The distance d2 ischosen to achieve adequate spot size modulation depth and depth of focusat the media surface.

The ratio of the distances d1/d2 determines the amount ofdemagnification of the image reflected from the media that occurs in alens. In a single lens design, this demagnification affects not onlyspot size but spot spacing. A demagnification of 1/4 gives a spot sizeof 0.005 mm which because of aberration is spread to an area 0.025 mm.If a single lens design had been used, the spacing of the spots wouldalso have been demagnified to 0.025 mm and significant crosstalk noisewould result. By using individual lenses, spaced approximately 0.200 mm,the detectors can be spaced at about 0.220 mm and thereby eliminatecrosstalk noise using the 0.025 mm light spots.

FIG. 2 is a side view of a magnetic floppy disk head 5 with an opticaltracking assembly according to a preferred embodiment of the invention.Head 5 is mounted, in arm 3 by known means not shown, for the extensionacross the various tracks of media 31. Head 5 is electrically connectedto read and write circuits and tracing control circuits by a flexibleprinted circuit 7. A recess 9 of approximately two millimeters by onepoint six millimeters and four and a half or five millimeters deep isprovided in head 5 in which the optical assembly comprising substrate 11is mounted and connected to flexible printed circuit 7. It will beappreciated that the same assembly techniques and methods of theinvention may be used to assemble optical disk read heads, as well asmagnetic disk heads with optical tracking.

Referring now to FIG. 3, a first transparent substrate 11 comprisingfused silica or other optical material has component mounting metalizedpads or contact pads placed on its bottom surface 13, such as usingsubstrate fiducial marks or indicia and accurately alignedphotolithographic masks and metal deposition steps known in the art ofmicroelectronic circuit manufacture. In this preferred embodiment,surface 13 of substrate 11 is approximately 1.6 mm by 2 mm and thesubstrate 11 is approximately 0.8 mm thick. A laser chip 15 is mountedto the surface 13 by means of some of the mentioned metalized pads. Asshown in FIG. 4, laser 15 is an edge emitting laser with the laser lightdirected upwards through means of a precision mirror 33 as shown in FIG.4. It will by understood that the edge emitting laser 15 can be replacedwith a vertical cavity surface emitting laser and thereby obviate theneed for the precision mirror in order to direct the laser beam normalto the substrate surface.

An optical detector chip 17 is also mounted to the component surface ofsubstrate 11 by means of the metalized pads. A hologram surface 19 onthe opposite side of substrate 11 carries the diffractive opticalelements shown in detail in FIG. 7. The diffractive optical elementphase profiles are designed using the computer calculations andmanufactured using techniques taught by Swanson et al. in U.S. Pat. No.5,161,059, the entire disclosure of which is incorporated herein byreference.

The optical elements are created photolithographically using the samefiducial marks or indicia used to place the metalized pads. Alternatelysecond fiducial marks that have been aligned with the first marks may beused to align the masks that are also used to create the opticalelements. In this way, when the light source, mirror and detector aremounted on their metalized pads, the optical paths among the devices andthrough the optical elements are in optical alignment as shown moreclearly in FIGS. 3 and 4. The precision mirror, if needed forredirecting light from an edge emitting laser, is considered to be adevice for the purposes of this description only because of the way itis mounted using metalized pads and solder as a silicon chip would bemounted. The hologram surface 19 also has the attachment areas 23 thatattach the first transparent substrate 11 with a second transparentsubstrate 21. These attachment areas and later described alignment areasare shown in detail in FIGS. 11 and 12.

The second substrate 21 carries the refractive optics in a surface 25that provides the second lens of lens pairs or doublets. Light fromlaser 15 is shaped and split by a diffractive optical element inhologram surface 19 into five separate beams of light that are directedthrough substrate and travel approximately 2.4 mm to the media. Only thechief ray of each beam is shown in FIG. 3 for clarity of thedescription. One beam is used for intensity feedback to control theelectrical power to laser 15. The other four beams are used for mediaposition or tracking detection. The beams of coherent light arereflected from media 31 and return through second substrate 21 and firstsubstrate 11 to be detected by detector 17. Since the elements are allin their designed optical alignment by virtue of the placement of themetalization pads, there is no need to energize the laser and move theelements relative to each other to bring them into optical alignment. Inother words, passive alignment is used rather than the active alignmentrequiring operation of the laser as in the prior art. It will berecognized that although the beams preferably pass first through thediffractive optical element in surface 19, the order of the opticalelements in the light path could be changed or the elements could becombined into one more complex element without departing from the scopeof the invention.

FIG. 4 is another side view of the assembly of FIG. 3. As shown in FIG.4, the light emitted by edge emitting laser 15 comes out substantiallyparallel to the plane of component surface 13 and must be directednormal to the component surface by the 45 degree surface of mirror 33.The light can then pass through substrate 11, a diffractive opticalelement in surface 19, a refractive lens 61 in surface 25, substrate 21and be reflected from media 31 as shown in FIGS. 1 and 3.

FIG. 5 is a plan top view of the component surface 13 looking downthrough transparent substrate 11. Electrical contact metalizations 39,41, 43 and 45 provide electrical connections to detecting photo-diodesin detector 17. Centered under detector 17 is a metalized area 53 havingthree apertures through which light reflected from media 31 is received.Solder ball alignment areas 47 on each side of area 53 serve both aselectrical contacts and as alignment mechanisms in this embodiment. Theareas 49 are also solder ball pads and serve to align and connect thelaser 15 to the first substrate and provide current to laser 15. Areas51 on the other hand only provide mechanical alignment and mechanicalattachment of mirror 33 to first transparent substrate 11.

The hologram surface 19 appears in FIG. 6 in plan view, again lookingdown onto substrate 11. Hologram surface 19 has metalized area 55 whichacts as a mask to reduce stray light but allow three beams created bydiffractive optics from the light from laser 15 to be directed to media31 from which they are reflected to reach detector 17 through the fiveapertures shown in metalized areas 59. Surrounding metalized area 55 isa diffraction grating 57 that scatters stray light from laser 15 so thatit does not adversely affect detector 17.

FIG. 7 shows the refractive lens surface 25, again in plan view lookingdown, this time through substrate 21. Lens 61 in combination with thediffractive optical elements in mask 55 shape and focus the laser lightinto three spots of approximately 20 μm diameter and spaced atapproximately 100 μm onto media 31. Lenses 63 and 65 focus the lightreflected from media 31 through mask 59 to detector 17 for positioncontrol and/or reading. Lens 67 focuses reflected light to thephoto-diode of detector 17 that provides an intensity level signal tothe power control circuits which control the electrical power providedto laser 15.

Surrounding both surface 19 and surface 25 is an attachment area showngenerally as area 71 in FIGS. 6 and 7. Area 71 contains spacing standoff benches and is the area in which an adhesive is placed in order tojoin substrate 21. The standoff benches passively define a proper ordesired vertical spacing or alignment. Preferably the adhesive isultraviolet light cured adhesive that can be laid down without concernfor time to harden. The adhesive is placed in areas 71 and then afterthe substrates 11 and 21 are aligned, the assembly is flooded withultra-violet light to catalyze the adhesive.

In an alternate embodiment, the adhesive is replaced withphotolithographically placed metalization pads and the two substratesare joined using solder ball technology.

FIG. 8 shows three diffractive optical elements 73, 75 with mask 55.These three elements provide the five beams of light to be reflectedfrom the media, the three main rays of which are shown in FIG. 3.Element 75 provides the power control beam that is reflected from themedia and is received at aperture 79 in mask 59 as shown in FIG. 8.Elements 73 and 77 each provide two beams that interfere at the mediasurface to create a dark band with two light bands on either side of thedark bands. The light bands are reflected back down to the pairs ofapertures 81, 83 and 85, 87 shown in FIG. 8 to provide the varying lightintensity that is used to detect an optical track on the media. Theapertures 73, 75 and 77 containing diffractive elements are eachapproximately 100 μm long and 20 μm wide.

Referring now to FIG. 9, the apertures of FIG. 8 are shown enlarged. Theends of each aperture 73, 75 and 77 are provided with an irregularboundary that change the orientation of the interference fringes so thatthey are not parallel with the optical track being detected and accuracyis improved.

FIG. 10 shows the two substrates 11 and 21 prior to their beingassembled into optical assemblies and diced. Because each element hasbeen accurately placed on each substrate using photolithography, theentire wafers can be aligned and joined prior to being diced into chipswithout the need to energize any of the laser devices on the substrate11. FIG. 10 shows the substrates inverted from the way they are shown inFIGS. 2, 3 and 4 in order to show the lasers, mirrors and detectors inplace on top of each die.

Prior to putting the wafers together, the adhesive material 23 is placedin the area 71 of each die on at least one of the wafers. After theadhesive is placed, the two wafers are placed one above the other andaligned. In one embodiment of the invention, a known photolithographicmask aligning tool is used with vernier fiduciary marks 93 and 95 tomonitor the relative displacement of the two substrates until they arein alignment with each other. The substrate 11 can then be lowered ontosubstrate 21, the alignment rechecked, and the adhesive catalyzed byultraviolet light.

In another embodiment, the two wafers are passively aligned using thealignment means 91. Three forms of alignment means are contemplated andshown in FIGS. 11A, 11B and 11C. One, shown in FIG. 11A, takes the formof V-shaped grooves 97 etched into matching faces of the substrates 11and 21. These grooves are then aligned with sphere 99 to index the twowafers into alignment. Note that only a few grooves and spheres areneeded to align all of the dies while they are still together as awafer. Another embodiment of the alignment means, shown in FIG. 11B,comprises photolithographically placed metalization pads 101 which arethen connected by reflowing a solder ball 103. In a still furtherembodiment of FIG. 1C, a bench 105 is raised by etching the surroundingsurface and the bench 105 is indexed into a recess 107, also created byphotolithographically placed etchant, preferably reactive ion etchant.

In the adhesive area 71 of each die, means may be needed to accuratelyspace the two substrates from each other. Spacing is accomplished in oneembodiment by means of a bench 109 shown in FIG. 1D. Three or morebenches 109 are located in the area 71 around each die in an adhesivewith high compressive.

In another embodiment, the solder bumps or balls and metalizations areused in area 23 accomplishing both attachment and alignment as shown inFIG. 11B. Alternately, when an adhesive with high compressive strengthis chosen, only three or more such benches are needed for spacing theentire wafers and after the adhesive has set, the joined wafers can bediced without substrate spacing.

Referring now to FIG. 12, a method of photolithographically placing anoptical element on a substrate surface 25 in alignment with diffractiveelements and/or electrical devices is shown. A refractive opticalelement in the form of a microlens 115 is formed by placing a circularlayer of photoresist 111 on a surface of optical material using a mask.The photoresist is then partially flowed using controlled heat so thatthe photoresist assumes a partially spherical shape 113. Thereafter, thesurface 25 is etched and a refractive element 115 having substantiallythe same shape as the photoresist 113 is formed by the variable etchrate of the continuously varying thickness of the photoresist 113. Inthe event that a hybrid optical element is desired, the microlens 115 isfurther processed by etching or embossing steps.

In one embodiment, a layer of photoresist 117 is placed over themicrolens 115 and exposed through a photolithographic mask with thephase pattern of a diffractive optical element. When the exposedphotoresist is then developed, the surface of the microlens can befurther etched with the diffractive optical element pattern to produce ahybrid optical element 119. In another embodiment, a polymer is placedover the microlens in place of the photoresist and the phase pattern isembossed into the polymer as shown at 121. It also will be understoodthat although a convex element has been shown, the same technique can beused to create a concave microlens.

Having described the invention in terms of preferred embodimentsthereof, it will be recognized by those skilled in the art of opticalsystem design that various further changes in the structure and detailof the implementations described can be made without departing from thespirit and scope of the invention. By way of example, the diffractiveoptical elements may be placed on the same surface of a substrate onwhich the electronic components are accurately placed with thesediffractive optical elements using photolithography. Likewise refractiveoptical elements may be placed using photolithography in alignment onthe other surface of the same substrate thereby allowing an entireoptical assembly to be fabricated using but one substrate without theneed for actively energizing a light source in the assembly toaccomplish alignment.

In the drawings and specification, there have been disclosed illustratedpreferred embodiments of the invention, and although specific terms areemployed, the terms are used in a descriptive sense only and not forpurposes of limitation. The invention has been described in considerabledetail with specific reference to these illustrated embodiments. It willbe apparent, however, that various modifications and changes can be madewithin the spirit and scope of the invention as described in theforegoing specification and as defined in the appended claims.

That which is claimed:
 1. An apparatus for use with data storage mediaand comprising:an integrated optical head comprisinga first substratebeing optically transparent and having opposing first and second faces,a light source positioned on the first face of said first substrate foremitting light through said first substrate and toward the data storagemedia, an optical detector on the first face of said first substrate fordetecting light reflected from the data storage media and through saidsubstrate, at least one first optical element on said first substrateand positioned in an optical path between said light source and saidoptical detector, and first passive alignment means for passivelyaligning said first substrate and at least one of either said lightsource or said optical detector, said first passive alignment meanscomprising a first plurality of contact pads on the first face of saidfirst substrate, a second plurality of contact pads on at least one ofsaid light source and said optical detector, and a plurality of solderbumps between said first and second plurality of contact pads topassively align said first substrate and at least one of said lightsource and said optical detector; and head positioning means forpositioning said integrated optical head relative to the data storagemedia.
 2. An apparatus according to claim 1 further comprising aplurality of electrical connections on the second face of said firstsubstrate; and wherein at least one of said light source and saidoptical detector is electrically connected to said electricalconnections on the first face of said first substrate via said pluralityof solder bumps.
 3. An apparatus according to claim 1 wherein said firstpassive alignment means comprises mechanical mating means between thefirst face of said first substrate and at least one of said light sourceand said optical detector.
 4. An apparatus according to claim 3 whereinsaid mechanical mating means comprises a plurality of mating featuresdefined between the first face of said first substrate and at least oneof said light source and said optical detector.
 5. An apparatus for usewith data storage media and comprising:an integrated optical headcomprisinga first substrate being optically transparent and havingopposing first and second faces, a light source positioned on the firstface of said first substrate for emitting light through said firstsubstrate and toward the data storage media, an optical detector on thefirst face of said first substrate for detecting light reflected fromthe data storage media and through said substrate, at least one firstoptical element on said first substrate and positioned in an opticalpath between said light source and said optical detector, first passivealignment means for passively aligning said first substrate and at leastone of either said light source or said optical detector, a secondsubstrate positioned adjacent said first substrate, said secondsubstrate being optically transparent and having opposing first andsecond faces, and at least one second optical element on said secondsubstrate in the optical path between said light source and said opticaldetector; and head positioning means for positioning said integratedoptical head relative to the data storage media.
 6. An apparatusaccording to claim 5 further comprising second passive alignment meansfor passively aligning said first substrate and said second substrate sothat said at least one second optical element is aligned in the opticalpath between said light source and said optical detector.
 7. Anapparatus according to claim 6 wherein said second passive alignmentmeans comprises:a third plurality of contact pads on the second face ofsand first substrate; a fourth plurality of contact pads on the firstface of said second substrate; and a plurality of solder bumps betweensaid third and fourth plurality of contact pads to passively align saidfirst substrate and said second substrate.
 8. An apparatus according toclaim 6 wherein said second passive alignment means comprises mechanicalmating means between said second face of said first substrate and saidfirst face of said second substrate.
 9. An apparatus according to claim8 wherein said mechanical mating means comprises a plurality ofmechanically mating features.
 10. An apparatus according to claim 5wherein said at least one second optical element comprises:a firstrefractive optical element positioned in the optical path between saidlight source and the data storage media, and a second refractive opticalelement positioned in the optical path between the data storage mediaand said optical detector.
 11. An apparatus according to claim 5 whereinsaid at least one second optical element comprises a hybrid opticalelement including diffractive and refractive portions.
 12. An apparatusfor use with data storage media and comprisingan integrated optical headcomprising a first substrate being optically transparent and havingopposing first and second faces, a light source positioned on the firstface of said first substrate for emitting light through said firstsubstrate and toward the data storage media, an optical detector on thefirst face of said first substrate for detecting light reflected fromthe data storage media and through said substrate, at least one firstoptical element on said first substrate and positioned in an opticalpath between said light source and said optical detector, said at leastone first optical element comprising a hybrid optical element includingdiffractive and refractive portions, and first passive alignment meansfor passively aligning said first substrate and at least one of eithersaid light source or said optical detector; and head positioning meansfor positioning said integrated optical head relative to the datastorage media.
 13. An apparatus for use with data storage media andcomprising:an integrated optical head comprising a first substrate beingoptically transparent and having opposing first and second faces, alight source positioned on the first face of said first substrate foremitting light through said first substrate and toward the data storagemedia, said light source comprising an edge emitting light source, anoptical detector on the first face of said first substrate for detectinglight reflected from the data storage media and through said substrate,at least one first optical element on said first substrate andpositioned in an optical path between said light source and said opticaldetector, first passive alignment means for passively aligning saidfirst substrate and at least one of either said light source saidoptical detector, and a mirror connected to the first face of said firstsubstrate and in the optical path between said light source and saidoptical detector; and second passive alignment means for passivelyaligning said mirror and said first substrate; and head positioningmeans for positioning said integrated optical head relative to the datastorage media.
 14. An integrated optical head for use with data storagemedia, said integrated optical head comprising:a first substrate beingoptically transparent and having opposing first and second faces; alight source positioned on the first face of said first substrate foremitting light through said first substrate and toward the data storagemedia; an optical detector on the first face of said first substrate fordetecting light reflected from the data storage media and through saidfirst substrate; at least one first optical element on said firstsubstrate and positioned in an optical path from said light source tosaid optical detector, said at least one first optical elementcomprising at least one of a diffractive optical element and arefractive optical element; and mechanical mating means between saidfirst face of said first substrate and said light source and saidoptical detector for passively aligning said substrate and at least oneof either said light source or said optical detector.
 15. An integratedoptical head for use with data storage media, said integrated opticalhead comprising:a first substrate being optically transparent and havingopposing first and second faces; a light source positioned on the firstface of said first substrate for emitting light through said firstsubstrate and toward the data storage media; an optical detector on thefirst face of said first substrate for detecting light reflected fromthe data storage media and through said first substrate; at least onefirst optical element on said first substrate and positioned in anoptical path from said light source to said optical detector, said atleast one first optical element comprising a hybrid optical elementincluding diffractive and refractive portions; and mechanical matingmeans between said first face of said first substrate and said lightsource and said optical detector for passively aligning said substrateand at least one of either said light source or said optical detector.16. An integrated optical head for use with data storage media, saidintegrated optical head comprising:a first substrate being opticallytransparent and having opposing first and second faces; a firstplurality of contact pads on the first face of said first substrate; alight source positioned on the first face of said first substrate foremitting light through said first substrate and toward the data storagemedia; an optical detector on the first face of said first substrate fordetecting light reflected from the data storage media and through saidfirst substrate; a second plurality of contact pads on at least one ofsaid light source and said optical detector; at least one first opticalelement on said first substrate and positioned in an optical pathbetween said light source and said optical detector; and a plurality ofsolder bumps between either said first or second plurality of contactpads for passively aligning said first substrate and at least one ofsaid light source and said optical detector.
 17. An integrated opticalhead according to claim 16 further comprising a plurality of electricalconnections on the second face of said first substrate; and wherein atleast one of said light source and said optical detector is electricallyconnected to said electrical connections on the first face of said firstsubstrate via said plurality of solder bumps.
 18. An integrated opticalhead according to claim 16 wherein said at least one first opticalelement comprises at least one of a diffractive optical element and arefractive optical element; and wherein said at least one first opticalelement is on at least one of the first face and the second face of saidfirst substrate.
 19. An integrated optical head according to claim 16wherein said at least one first optical element comprises a hybridoptical element including diffractive and refractive portions.
 20. Anintegrated optical head according to claim 16 further comprising:asecond substrate positioned adjacent said first substrate, said secondsubstrate being optically transparent and having opposing first andsecond faces; and at least one second optical element on said secondsubstrate.
 21. An integrated optical head according to claim 20 furthercomprising passive alignment means for passively aligning said firstsubstrate and said second substrate so that said at least one secondoptical element is aligned in the optical path between said light sourceand said optical detector.
 22. An integrated optical head according toclaim 20 wherein said at least one second optical element comprises:afirst refractive optical element positioned in the optical path fromsaid light source toward said data storage media; and a secondrefractive optical element positioned in the optical path from the datastorage media to said optical detector.
 23. An integrated optical headaccording to claim 20 wherein said at least one second optical elementcomprises at least one of a diffractive optical element and a refractiveoptical element.
 24. An integrated optical head according to claim 20wherein said at least one second optical element comprises a hybridoptical element including diffractive and refractive portions.
 25. Anintegrated optical head for use with data storage media, said integratedoptical head comprising:a first substrate being optically transparentand having opposing first and second faces; a light source positioned onthe first face of said first substrate for emitting light through saidfirst substrate and toward the data storage media; an optical detectoron the first face of said first substrate for detecting light reflectedfrom the data storage media and through said first substrate; at leastone first optical element on said first substrate and positioned in anoptical path from said light source to said optical detector; andmechanical mating means between said first face of said first substrateand said light source and said optical detector for passively aligningsaid substrate and at least one of either said light source or saidoptical detector, said mechanical mating means comprising a plurality ofmechanically mating features defined between the first surface of saidfirst substrate and at least one of said light source and said opticaldetector.
 26. An integrated optical head for use with data storagemedia, said integrated optical head comprising:a first substrate beingoptically transparent and having opposing first and second faces; alight source positioned on the first face of said first substrate foremitting light through said first substrate and toward the data storagemedia; an optical detector on the first face of said first subtsrate fordetecting light reflected from the data storage media and through saidfirst substrate; at least one first optical element on said firstsubstrate and positioned in an optical path from said light source tosaid optical detector; a second substrate positioned adjacent said firstsubstrate, said second substrate being optically transparent and havingopposing first and second faces; at least one second optical element onsaid second substrate; and mechanical mating means between said firstface of said first substrate and said light source and said opticaldetector for passively aligning said substrate and at least one ofeither said light source or said optical detector.
 27. An integratedoptical head according to claim 26 further comprising;passive alignmentmeans for passively aligning said first substrate and said secondsubstrate so that said at least one second optical element is aligned inthe optical path between said light source and said optical detector.28. An integrated optical head according to claim 26 wherein said atleast one second optical element comprises:a first refractive opticalelement positioned in the optical path between said light source anddata storage media; and a second refractive optical element positionedin the optical path between the data storage media and said opticaldetector.
 29. An integrated optical head according to claim 26 whereinsaid at least one second optical element comprises at least one of adiffractive optical element and a refractive optical element.
 30. Anintegrated optical head according to claim 26 wherein said at least onesecond optical element comprises a hybrid optical element includingdiffractive and refractive portions.
 31. A method for making anintegrated optical head for use with data storage media, the methodcomprising the steps of:providing a first transparent substrate havingopposing first and second faces; forming at least one first opticalelement on the first transparent substrate; positioning a light sourceand an optical detector on the first face of the first substrate foremitting light through said first substrate and toward the data storagemedia and detecting light reflected from the data storage media andthrough said substrate; passively aligning the first substrate and atleast one of either said light source or said optical detector;providing a second transparent substrate comprising at least one secondoptical element; and passively aligning the second transparent substratewith the second surface of the first transparent substrate so that theat least one second optical element is positioned in an optical pathbetween the light source and the optical detector.
 32. A methodaccording to claim 31 wherein the steps of providing the first andsecond transparent substrates comprises providing first and secondtransparent wafers; and wherein the step of passively aligning the firstand second substrates comprises passively aligning the first and secondwafers.
 33. A method according to claim 32 further comprising the stepsof securing the aligned first and second wafers together; and dicing thewafers into a plurality of integrated optical devices.
 34. An articleduring the manufacture of a plurality of integrated optical heads, saidarticle comprising:a first wafer being optically transparent and havingopposing first and second faces, and a plurality of light sources andoptical detectors on a first face of said first wafer; a second waferbeing optically transparent and having opposing first and second faces,and a plurality of optical elements on said second wafer; and passivealignment means for passively aligning said first wafer and said secondwafer so that said plurality of light sources and optical detectors arealigned with said plurality of optical elements.
 35. An articleaccording to claim 34 wherein said passive alignment means comprises:afirst plurality of contact pads on the second face of said first wafer;a second plurality of contact pads on the first face of said secondwafer; and a plurality of solder bumps between said first and secondplurality of contact pads to passively align said first wafer and secondwafers.
 36. An article according to claim 34 wherein said passivealignment means comprises mechanical mating means between said secondface of said first wafer and said first face of said second wafer. 37.An article according to claim 36 wherein said mechanical mating meanscomprises a plurality of mechanically mating features defined in thesecond surface of said first wafer and the first face of said secondwafer.
 38. An article according to claim 34 wherein aid passivealignment means comprises alignment indicia on said first wafer and saidsecond wafer.
 39. An article according to claim 34 further comprising anadhesive for securing said first and second wafers together.
 40. Anarticle according to claim 34 wherein said plurality of optical elementscomprises diffractive optical elements.
 41. An article according toclaim 34 wherein said plurality of optical elements comprises refractiveoptical elements.
 42. An article according to claim 34 wherein saidplurality of optical elements comprises hybrid optical elements, eachincluding diffractive and refractive portions.
 43. A method for makingan integrated optical head for use with data storage media, the methodcomprising the steps of:providing a first transparent substrate havingopposing first and second faces; forming at least one first opticalelement on the first transparent substrate; positioning a light sourceand an optical detector on the first face of the first substrate foremitting light through said first substrate and toward the data storagemedia and detecting light reflected from the data storage media andthrough said substrate; and passively aligning the first substrate andat least one of either said light source or said optical detector, thestep of passively aligning comprising the steps forming a firstplurality of contact pads on the first face of the first substrate,forming a second plurality of contact pads on at least one of either thelight source or the optical detector, and forming a plurality of solderbumps between the first and second plurality of contact pads topassively align the first substrate and at least one of the light sourceand the optical detector.
 44. A method according to claim 43 wherein thesteps of forming the first and second pluralities of contact padscomprises forming the first and second pluralities of contact pads usingforming same using photolithography.
 45. An optical system comprising:afirst transparent substrate having alignment areas photolithographicallyplaced on a first face and at least one diffractive optical elementphotolithographically formed in a second face, the photolithography ofthe first face being aligned with the photolithography of the secondface; at least one electronic device mounted to said first face by saidalignment areas causing passive optical alignment between saidelectronic device and said diffractive optical element; substratealignment areas on the second face of said first transparent substrate;and a second transparent substrate having mating substrate attachmentareas on a first face for attaching said first transparent substrate inalignment with said second transparent substrate.
 46. An optical systemaccording to claim 45 wherein said substrate attachment areas furthercomprises photolithographically placed metalization pads and solderballs.
 47. An optical system according to claim 45 wherein said firsttransparent substrate is part of a first wafer and said secondtransparent substrate is part of a second wafer, said first transparentsubstrate and said second transparent substrate having been aligned byalignment of fiducial marks on said first wafer with fiducial marks onsaid second wafer respectively, said wafers having been attached to eachother by said attachment areas prior to being diced into separateassemblies.
 48. An optical system according to claim 45 furthercomprising refractive optical elements on a face of said secondtransparent substrate.
 49. An optical system according to claim 45wherein said system is a media reader and said at least one electronicdevice further comprises:a light source light source; and a plurality oflight detectors.
 50. An optical system according to claim 49 whereinsaid at least one diffractive optical element which divides the lightfrom said light source into a plurality of beams for reflection fromsaid media, each reflected beam having an individual refractive lens onthe first surface of said second transparent substrate for transmittingsaid reflected beam to a detector.
 51. An optical system according toclaim 45 further comprising:a light source light source mounted to thefirst face of said first transparent substrate by said alignment areas,said diffractive optical element divides light from said light sourceinto a plurality of beams for refection from a media; a detector devicehaving a plurality of light sensitive areas, said detector being mountedto the first face of said first transparent substrate by said alignmentareas; and a plurality of refractive optical elements on the firstsurface of said second transparent substrate, each reflected beampassing through an individual refractive lens on the first surface ofsaid second transparent substrate for transmitting said reflected beamto one of said light sensitive areas of said detector.
 52. An integratedoptical system comprising:a first transparent substrate having a lightsource and a light detector on a first face and at least on alignmentarea on a second face; a second transparent substrate mounted to thesecond face, the mounting including a mating alignment area on thesecond transparent substrate for mating with the alignment area andcausing passive optical alignment between the first transparentsubstrate and the second transparent substrate; a holographic opticalelement formed in the second face of the first transparent substrate fordirecting light from the light source to a remote target; and arefractive lens formed in a first face of the second transparentsubstrate for directing light from the light source received through thefirst holographic optical element to the remote target.
 53. Anintegrated optical system according to claim 52 further comprising:asecond refractive lens formed in the first face of said secondtransparent substrate for directing light from the remote target to thedetector.
 54. An integrated optical system according to claim 53 furthercomprising a third refractive lens formed in the first face of saidsecond transparent substrate for directing light from the remote targetto a light intensity detector.
 55. An integrated optical systemaccording to claim 52 wherein said first and second substrates comprisefused silica.
 56. An integrated optical system according to claim 52wherein:the alignment area further comprises a metalized area ofpredetermined size and position; the mating alignment area furthercomprises a metalized area of predetermined size and position; and themounting further comprising solder of predetermined volume and liquifiedsurface tension for passively pulling the first transparent substrateand the second transparent substrate into horizontal alignment andmaintaining the second substrate a predetermined distance from the firsttransparent substrate.
 57. An integrated optical system according toclaim 52 wherein:the alignment area further comprises an alignment benchof predetermined height and position; the mating alignment area furthercomprises an alignment recess of predetermined depth and position; andthe mounting further comprising adhesive, the bench and the recessinteracting to maintain the first transparent substrate and the secondtransparent substrate in horizontal alignment and to maintaining thesecond substrate a predetermined distance from the first transparentsubstrate.
 58. An integrated optical system according to claim 52wherein the light source further comprises a semiconductor light sourceadjacent to an angled mirror, the light source and the mirror mountedand aligned with each other and aligned with the holographic opticalelement by flip chip solder bonds.
 59. An integrated optical systemaccording to claim 52 wherein the holographic optical element formed inthe second face of the first transparent substrate further comprises:ametal layer defining an aperture and a binary grating surrounding theaperture for dispersing stray light; and a diffractive optical elementlocated within the aperture for directing light from the light source tothe remote target.
 60. An apparatus for use with data storage media andcomprising:an integrated optical head comprisinga first substrate beingoptically transparent and having opposing first and second faces, alight source positioned on the first face of said first substrate foremitting light through said first substrate and toward the data storagemedia, an optical detector on the first face of said first substrate fordetecting light reflected from the data Storage media and through saidsubstrate, at least one first optical element on said first substrateand positioned in an optical path between said light source and saidoptical detector, and first passive alignment means for passivelyaligning said first substrate and at least one of either said lightsource or said optical detector, said first passive alignment meanscomprising mechanical mating means between the first face of said firstsubstrate and at least one of said light source and said opticaldetector; and head positioning means for positioning said integratedoptical head relative to the data storage media.
 61. An apparatusaccording to claim 60 wherein said mechanical mating means comprises aplurality of features defined between the first face of said firstsubstrate and at least one of said light source and said opticaldetector.
 62. An apparatus for use with data storage media andcomprising:an integrated optical head comprisinga first substrate beingoptically transparent and having opposing first and second faces, alight source positioned on the first face of said first substrate foremitting light through said first substrate and toward the data storagemedia, an optical detector on the first face of said first substrate fordetecting light reflected from the data storage media and through saidsubstrate, at least one first optical element on said first substrateand positioned in an optical path between said light source and saidoptical detector, said at least one first optical element comprising atleast one of a diffractive optical element and a refractive opticalelement, said at least one first optical element being positioned on atleast one of the first face and the second face of said first substrate,and first passive alignment means for passively aligning said firstsubstrate and at least one of either said light source or said opticaldetector; and head positioning means for positioning said integratedoptical head relative to the data storage media.
 63. A method for makingan integrated optical head for use with data storage media, the methodcomprising the steps of:providing a first transparent substrate havingopposing first and second faces; forming at least one first opticalelement on the first transparent substrate; positioning a light sourceand an optical detector on the first face of the first substrate foremitting light through said first substrate and toward the data storagemedia and detecting light reflected from the data storage media andthrough said substrate; and passively aligning the first substrate andat least one of either said light source or said optical detector, thepassively aligning step comprising the step of forming mechanicallymating features between the first surface of the substrate and at leastone of the light source and the optical detector, and relativelypositioning the first substrate and at least one of the light source andthe optical detector so that the mechanically mating features engage oneanother.
 64. An integrated optical system comprising:a transparentsubstrate having alignment areas photolithographically placed on a firstface and at least one hybrid optical element photolithographicallyformed in a second face, the photolithography of the first face beingaligned with the photolithography of the second face, the hybrid opticalelement comprising a metal layer defining an aperture, a binary gratingsurrounding the aperture for dispersing stray light, and a diffractiveoptical element located within the aperture for directing light from alight source in the electronic device to a media; and at least oneelectronic device mounted to said first face by said alignment areascausing passive optical alignment between said electronic device andsaid hybrid optical element.